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(No Model.) 2 sheets-sheet l1.

' W.- G. A. BONWILL. NoGK DRILL AND INSTRUMENT USING IIBVOLVING NAMMNRS.

No. 425,737. Patented @17.15.1890.

WITNESSES (No Model.) 2 Sheets-Sheet 2. W. G. A.' BONWILL. ROCK DRILL AND INSTRUMENT USING REVOLVING HAMMERS.

No. 425,737. Patented Apr. 15, 1890.

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v UNITED STATES PATENT OFFICE.;

WILLIAM G. A. BONlVILL, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO TI-IE S. S. VHITE DENTAL MANUFACTURING COMPANY, OF SAME PLACE.

ROCK-DRILL AND INSTRUMENT' USING Ril-:voLvlNe HAMMERS.

SPECIFICATION forming part of Letters Patent No. 425,737', dated April 15, 1890.

Application filed December 2l, 1886. Serial No. 222,205. (No model.)

T all whom it may concern.'

Be it known that I, WILLIAM G. A. BON- WILL, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania., have invented certain new and useful Improvements in Rock- Drills and Instruments Using Revolving Hammers; and I do hereby declare the follow` ing to be a full, clear, and exact description ro of the invention, such as will enable others skilled in the artto which it appertains to make and use the same.

My invention relates to improvements in rock-drills and other instruments using a rex 5 volving hammere-such, for instance, as dental pluggers. The revolving hammer is a rapidly-revolving wheel or part having a hammer lug or projection on its periphery, which at every revolution of the Wheel strikes upon the end of a tool-carrying spindle, so as to impart a rapid succession of blows thereto and enable the tool at the opposite end of the spindle to do its work.

The object of my invention is to improve the construction of instruments of this class,

. so that they are better adapted for the per-- formance of the work for which they are intended.

The subject-matter claimed herein as my invention is first described in detail as embodied and organized in the best way now known to me, and is then distinctly recited in the claims at the close of this specification.

In the accompanying drawings, which show my improvements asorganized more particularly for use as a rock-drill, Figure l is a view lin side elevation of the improved instrument. Fig. 2 is a like view at right angles to that depicted in Fig. l, partly in longitudinal section. Fig. 3 is a side view of the revolving hammer detached; and Fig. 4, a side and an end view of said hammer, showing a vmodification of the hammer projection thereof. Fig. 5 is a side view of a modification of the in- 4 5 strument, showing it as adapted for operation by manual power through crank-handles and toothed gearing.

A forked frameA is fitted with a transverse axle pin or shaft a, with which a revolving 5o hammer wheel or arm B is fitted to revolve freely when driven by a cord or belt pulley C, connected with the said hammer-wheel or by any other suitable form of gearing with the driving-power. I prefer to use the beltpulley and a driving bandpr belt to drive the rotating hammer wheel or arm B when the instrument is to be moved freely about in operation.' Jointed or j ournaled to the outer ends of the revolving axle or shaft ct of the revolving wheel B is the forked butt-end or 6c rear section D of the hand-piece'casing H P C, whereby said hand-piece casing may be rocked freely around its pivotal connection with the. frame A. The front end of said forked section D is tubular and internally screw-threaded to receive the male threads of the rear end of the section E of the hand,- piece casing. Fitted upon the front end of the casing-section E is the rear end of the front casing-section F, which constitutes the 7o Ylinger-piece or handle-section of the instrun ment. Said section F is iitted to turn freely on the front end of the section E, preferably by forming an annular groove f in said section F to receive a shoulder g of a plate G, attached to the section E by fastening-screws, for example.

The tool-carrying spindle H is tted to have a slight endwise movement inthe handpiece casing, the extent of which may be del8o termined by means of an annular groove h in said tool-carrying spindle, which is fitted to receive the reduced end or lug g on the plate G, which projects through a suitable opening in the casing-section E. In addition to the endwise movement or reciprocation of the tool-carrying spindle H in the hand-piece casing it has a revolving motion in the. cas-v ing-section E, while the front or hand-piece section F is keyed to said tool-carrying spingo dle, so as to turn with it without interfering with Jthe endwise movement of said spindle in Asaid front section F. This is permitted by means of a longitudinal groove h, (shown by dotted lines in Fig. 2,) in which the point of a set-screw f', passing through said section F, engages. It will therefore be understood that in the 'preferred organization the toolcarrying spindle has an endwise movement through the Whole of the hand-piece casing Ioo the spindle is not claimed herein, as it is a.

well-known tool-locking device in the art.

The periphery of the revolving hammer wheel or` arm BV is fitted with a hammer projection b, which in the revolution of said wheel strikes upon the end of the tool-carrying spindle H to impart a series of rapid blows thereto. This, broadly, is old; but I have improved thehalnmer projection in that, instead of a rigid projection or a hammer projection sliding radially, both ofwhich areobjectionable, I provide the said projection in the form of a revolving projection, preferably a roller, the curved periphery of which stan ds out from the'peripliery of' the revolving wheel or arm, so as to strike upon the end of the tool-carrying spindle to impart the blows thereto. The effect of the blows delivered by my roller-hammer projection, instead of the xed or sliding projection, as heretofore,

is substantially different, in that with they old forms of hammer projection a large portionof the blow was taken up by a side blow on the spindle and lateral thrust against the casing, while by my improvement the blow is a rolling one, almost wholly avoiding the side blow or thrust, while acting more eectively in imparting the blows which drive the spindle endwise. The blows are more distinct and positive than where the rigid or sliding hammer projection is employed.

The manner of attaching the rolling hammer proj ection in the periphery of the revolvplace by side plates attached to said wheel,

and in Fig. 4 the rolling hammer projection is shown as consisting of a small wheel let yinto the 'periphery of the hammer wheel or pivoted at t and carrying at its opposite end a spring-pawl t2, fitted to engage with a circular series of ratchet-teeth h2 on the end of the reciprocating spindle Il, whereby as the hammer-wheel is revolved the lever I is vibrated once for each revolution of said wheel and the toolcarrying spindle is turned for each of said revolutions a distance of one ratchet-tooth. It will therefore be seen that during the rotation ofthe hammer-wheel the spindle II is hit a rapid series of blows, and at the same time gradually turns to present the point of the operating-tool in dierent relations to the material operated upon.

A modied form of the instrument is shown in Fig. 5, in that it is driven by crank-handles and gearing and is provided with a stationary base or tripod.

AWhile I prefer the construction above described of my improvements embodied in an instrument the spindle of which may be intermittently rotated during the delivery of the blows by the pawl-and-ratchet device de-l inbefore set forth, of a frame, a revolving hammer fitted thereto, a peripheral rolling hammer projection of said hammer, a tubular casing, and a tool-carrying spindle fitted to reciprocate in said casing and having its buttend fitted to be struck by said roller projection of the revolving hammer, for the purposes set forth.

3. In a revolving hammertool,the combination of a bitactuatingspindle, an impactwheel, and a roller or sphere which is housed within said wheel and a portion of the pcripliery or surfaceof which projects beyond the periphery of said impact-wheel, substantially as described. f

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In testimony whereofl afiix my signature in ELI T. STARR, JAS. F. LYND. 

